Wire grid rack systems are a type of storage arrangement that includes a number of vertical posts collectively supporting wire grid racks. One type of configuration of wire grid rack systems involves modular “knock-down” storage arrangements and these have seen extensive use in both retail and residential environments. Such modular “knock-down” storage arrangements are typically comprised of generally four-sided shelves made up of intersecting wire rods, with each shelf separated and supported by a post at each corner above and below the respective shelf. The user assembles the shelving system by engaging a set of four posts to each of the four corners of a shelf, placing a second shelf on top of the posts, engaging another set of posts to the second shelf, and so on until the shelving system has the desired number of shelves. The shelving system can be disassembled (i.e., “knocked down”) merely by disengaging the posts from the shelves, and the posts and shelves can then be stored in a compact manner (e.g., in a box) for storage or transportation.
These modular “knock-down” storage arrangements have become popular because they are typically easy to assemble into an initial storage configuration. However, it is desirable that users can re-configure such modular “knock-down” storage arrangements to more suitably store a different mix of items at a later time after the initial set up. Additionally, it is desirable that users can more fully utilize the available space occupied by the storage arrangement via, for example, providing opportunities to store items in unoccupied areas within the confines or “footprint” of the storage arrangement.
One drawback in re-configuring modular “knock-down” storage arrangements from their initial storage configuration to another configuration is that it is often necessary to at least partially disassemble the storage arrangement and this can involve substantial effort and/or careful use of tools, U.S. Pat. No. 6,364,139 to Chen notes that some conventionally known sectional racks of this type require fastening tools to erect or disassemble the racks. However, according to U.S. Pat. No. 5,364,139 to Chen, improvements have been made to such sectional racks and fastening means and tools are no longer needed in the erection and disassembling thereof. Reference is had to FIG. 1 which is an enlarged exploded perspective view of a portion of a prior art wire grid rack system that, according to U.S. Pat. No. 6,364,139 to Chen, includes vertical posts 10 having a plurality of horizontally spaced annular grooves 13 provided on their outer surfaces, and shelves 12 connected to the vertical posts 10 through two-part connecting members 11. The two parts of the connecting member 11 may be opened or closed relative to each other. A radially inward projected rib 14 is annularly provided along an inner surface of the connecting member 11 at the proper position, such that, when the two parts of the connecting member 11 are in a closed position, it may be put around the vertical post 10 at a predetermined position by engaging the rib 14 with one of the grooves 13. The connecting member 11 in the closed position has a downward and outward inclined outer surface, making it look like a truncated cone. The shelf 12 has short sleeves 15 provided at four corners thereof (only one corner is shown in FIG. 1). Each sleeve 15 has a downward and outward inclined inner surface corresponding to the inclined outer surface of the connecting member 11. The sleeves 15 are separately put around the connecting members 11 mounted on the vertical posts 10 to, on the one hand, force the connecting members 11 toward the vertical posts 10 and, on the other hand, connect the shelves 12 to the vertical posts 10. In the above-described sectional rack, each shelf 12 is connected to the vertical posts 10 by putting four sleeves 15 thereof around four connecting members 11 mounted on the posts 10. If it is intended to increase or decrease the number of shelves 12 of the rack, it is necessary to temporarily remove the top shelf 12 from the rack before other layers of shelves 12 could be adjusted. According to U.S. Pat. No. 6,564,139 to Chen, it is inconvenient for the user to temporarily remove the top shelf 12 from the rack before other layers of shelves 12 are adjusted.
Thus, storage arrangements have been proposed that ease the transition from their initial storage configuration to another configuration. Still more flexibility has been sought, however, so that the variety of items that can be stored, and the accessibility of such stored items, can be increased. To this end, U.S. Pat. No. 7,325,697 to Lim et al notes that storage bins can be used to hold articles and objects, with the storage bins placed on the shelves of a modular “knock-down” storage arrangement in an organized manner. However, according to U.S. Pat. No. 7,325,697 to Lim et al, the use of conventional storage bins has certain disadvantages including, for example, the disadvantage that conventional storage bins are not secured to the shelves, so that a storage bin might slide about the shelf on which it is supported, especially if it is advertently pushed or tipped by a user or another object. This pushed or tipped storage bin may fall off a shelf, causing damage to the contents and possible injury to a person. U.S. Pat. No. 7,325,697 to Lim et al discloses a storage bin that can be engaged to the shelves of a modular “knock-down” storage arrangement in a manner which allows for safe and convenient access to the contents stored in the storage bin.
Despite the continued improvements to the above-described storage arrangements, a need exists for a shelf assembly that can be easily assembled and that can be easily installed at different heights without the need for any tools.